Cellulose sponges are in wide use for many cleaning applications. The process for providing cellulose sponges is environmentally disadvantageous due to toxic gaseous and liquid by-products.
Polyurethane sponge materials have been known and utilized for a long time. Most of these sponges are synthesized from isocyanate terminated polyethyleneoxide, polypropyleneoxide, polyesters, or combinations thereof. Coreactants are usually polyols or polyamines of similar polymeric backbones. Water is also used as a coreactant which generates a blowing agent (i.e. carbon dioxide) in addition to generating a crosslinked system. The majority of these materials produce a sponge material with little hydrophilic character (moderate bulk hydrophilicity, but poor surface properties), and few of the characteristics associated with a cellulose sponge. Materials which are claimed to be hydrophilic usually contain a sacrificial hydrophilic compound or have excessive swell (in excess of 50%).
Isocyanate terminated sulfopolyethyleneoxide prepolymers have been described in U.S. Ser. No. 562,459, now U.S. Pat. No. 4,558,149 and also in its CIP application, U.S. Ser. No. 739,542, filed May 30, 1985. Other sulfonated prepolymers for foam applications are described in U.S. Pat. No. 3,988,268. The use of sulfonated urethanes have otherwise been mainly restricted to the synthesis of water-soluble or water-dispersible materials, e.g. U.K. Pat. No. 1,483,687. Prepolymers based on isocyanate-terminated polyethyleneoxide are described in U.S. Pat. Nos. 4,160,076; 4,384,050; 4,384,051; and 4,377,645.